Glass prism-plate.



No. 627,848. v Patented lune 27, I899.

- G. FUGMAN.

GLASS PRISM PLATE.

(Application filed July 15, 1898.)

(Model) P WC E f a UNITED STATES PATENT OFFICE.

GODFREY FUGMAN, OF CLEVELAND, OlIlO.

GLASS PRISM-PLATE.

SPECIFICATION forming part of Letters Patent No. 627,848, dated June 27,1899.

Application filed July 15,1898. Serial No. 685,991. (Modeh) To all whomitmay concern:

Be it known that I, GODFREY FUGMAN,a citizen of the UnitedStates,residing at Cleveland, in the county of Cuyahoga and'State ofOhio, have invented a certain new and useful Improvement in GlassPrism-Plates,of which the following is a full, clear, and exactdescription, reference'being had to'the accompanying drawings.

The invention relates to a glass plate adapted for use as a window-glassor forsome analogous purpose,the object being to refract largequantities of brilliant light into interiors in the most usefuldirection.

The invention consists of a glass plate having one side made up of aplurality of rows of angular'faced prismatic lugs which are shaped andarranged substantially as shown in the drawings and as hereinafterdescribed.

In the drawings, Figure 1 is a rear View of the glass prism-plateembodying my invention. Fig. 2 is a vertical sectional view on line 2 2of Fig. 1. Fig. 2 is a view of the angular refracting-face of one of thelugs shown in Fig. 1. Fig. 3 is a rear view, and Fig. 4: is a sectionalside view, of a modified form of the invention. Fig. at is a view of theangular refracting-face of one of the lugs shown in Fig. Figs. 5 and Gare respectively a rear view and a sectional side view of anothermodified form of the invention, and Fig. 6 is a view of an angularrefracting-face of one of the lugs shown in Fig. 5. Figs. 7 and 8 arerespectively a rear view and a sectional side view of another modifiedform of the invention, and Figs. 8 and S are respectively views of theangular refracting-faces of the two forms of lugs shown in Fig. '7.

The front side a of theglass plate is preferably plane. The rear side ismade up of a plurality of angular-faced projecting prismatic lugs B G D,&c., which are arranged in-horizontal rows. The lugs in each row arestaggered with respect to the lugs in the rows above and below them.Each lug extends past the adjacent lugs in the rows above and below itforabout half their length-that is to say, the top of anylug liessubstantially midway between the top and bottom of the adjacent lugs inthe row above it, and the bottom of said lug is about midway between thetop and bottom of the adjacent lugs in the row below it. The sides ofeach lug are so shaped that they fit against the sides of the adjacentlugs in the rows above and below it. The top faces Z), c, and d of thelugs are preferably at right angles, or nearly so, to the general planeof the plate. All of said top faces in any row are in the same plane,and all of said planes are preferably parallel.

The refracting-faces b b 0 0 &c., of the lugs in the several rows arerespectively placed substantially as follows, to wit: All of said facesin any row are in the same plane, and the several planes containing therefraot ing-faces of the lugs in different rows are parallel to eachother and lie at an angle of thirtyfive degress, more or less, to thegeneral plane of the glass plate. The different uses to which the plateis adapted may render it desirable to form these refracting-faces atother angles to the general plane of the plate, as will be understood bythose familiar with the art. These oblique retracting-faces of the lugsare widest at their tops and bottoms and grow symmetrically narrower toward a line midway between said tops and bottoms. Itis because of thisform that the sides of each lug are adapted to match and contact withthe sides of adjacent lugs in the rows above and below it.

The glass plate has preferably a plain marginal edge a on all sides tofacilitate securing it in a suitable frame.

It will be noticed that in the described plate the total area of therefracting-surfaces is very large, being, in fact, larger than the areaof the flat surface of the plate on the front side thereof. It willfurther be noticed that there are no long grooves extending in anydirection across the plate. Such grooves have heretofore beencharacteristic of all prism-plates wherein the total area of therefracting-surfaces is large and wherein said refracting-surfaces lie inparallel planes at an angle to the plane of the front faceof the plate,and it is desirable that in all prismplates which are intended forrefracting light through a single'opening into a dark interior theserefracting-surfaces shall be in parallel planes. These long grooves areobjectionable for several reasons. In the first place, they cause therefracted light to be divided by long dark streaks. The principalobjection,

however, is that they weaken the plate, and

such plates as heretofore constructed have been so liable to break alongsaid grooves that it has been found practicallyimpossible to use platesmore than four or five inches square. These small plates or tiles, asthey are sometimes called, are necessarily secured in suitable framingin order to cover the opening through which the light passes. Thisframing intercepts a very considerable quantity of light which wouldotherwise pass through. In order that it shall intercept as little lightas possible, it is made of metal, and this is very expensive.

The plate heretofore described and having the construction pointed outin the claims may be made of any size, and because there are no longgrooves extending across it in any direction it is not liable to breakand does not need to he used in small pieces.

Having described my invention, I claim 1. Aglass prism-plate having oneside made up of a plurality of angular-faced prismatic lugs which arearranged in rows, each row containing a plurality of such lugs, whichare staggered with respect to the lugs in the rows above and below them,the upper part of each lug being between and in contact with the lowerpart of the adjacent lugs in the row above it, and its lower part beingbetween and in contact with the upper part of the adjacent lugs in therow below it, substantially as specified. I

r 2. A glass prism-plate having one side made up of a plurality ofangular-faced prismatic lugs which are arranged in rows, and each 1 rowcontaining a plurality of such lugs which are staggered with respect tothe lugs in the rows above and below them, the upper part of each lugbeing between and in contact with the lower part of the adjacent lugs inthe row above it, and its lower part being between and in contact withthe upper part of the adjacent lugs in the row below it, the angularrefracting-faces of all the lugs in anyrow being in the same plane whichis parallel to the plane in which the retracting-faces of the other rowsof lugs lie, substantially as specified.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses.

GODFREY FUGMAN. WVitnesses:

E. B. GILOHRIST, E. L. THURSTON.

